Science Olympiad Astronomy C Division Event Golden Gate Invitational University of California, Berkeley Berkeley, CA February 9, 2019 Team Number: Team Name: Instructions: 1) Please turn in all materials at the end of the event. 2) Do not forget to put your team name and team number at the top of all answer pages. 3) Write all answers on the lines on the answer pages. Any marks elsewhere will not be scored. 4) Do not worry about significant figures. Use 3 or more in your answers, regardless of how many are in the question. 5) Please do not access the internet during the event. If you do so, your team will be disqualified. 6) Feel free to take apart the test and staple it back together at the end! 7) Good luck! And may the stars be with you! 1
Section A: Use the Image Sheet to answer the following questions. The value of each sub-question is listed after the question. 1. 47 Tucanae is a globular cluster located about 4,000 pc from Earth. (a) Which image depicts this object in visible light? (1 pt) (b) Surveys of this cluster have revealed dense regions of compact binaries. Which image depicts these objects? (1) (c) Among the objects visible in the above image is 47 Tuc W. This object is under close study as a transitional stage between what two types of objects? (1) (d) Briefly (1 sentence) describe the method by which the first of these objects transitions to the other. (2) 2. Image 4 depicts an active galactic nucleus in the Canes Venatici constellation. (a) What is the Messier Catalogue number of this object? (1) (b) What large category of active galaxies does this object belong to, and how is it distinguished from the other primary category? (2) (c) This galaxy is known for its large population of black hole x-ray binaries, which are thought to be forming by what process? (1) 3. Image 12 depicts the Phoenix Cluster. (a) This object s vast reservoir of hot gas has led to what two major superlatives among galaxy clusters? (2) (b) Jets of high-energy particles are responsible for regions of low x-ray density. From where do these jets emanate? (1) (c) This production of jets mechanically manipulating material resembles the activity of radio galaxies. However, these jets also exhibit properties of another type of object. What type of object is this, and what properties indicate this? (2) 4. Image 5 is a composite image of x-ray and optical data of a spiral galaxy. (a) What is the name of the object being depicted? (1) (b) Which feature in this image is shown in x-ray light? (1) (c) What effect does this feature have on star formation within the galaxy? Briefly describe the process involved. (2) 2
5. M81 is a spiral galaxy in relatively close proximity to Earth. (a) Which image depicts this object? (1) (b) The image above was taken in infrared wavelengths. about M81 s composition? (1) This wavelength reveals what (c) M81 and M82, its neighboring galaxy, are both interacting to produce newborn stars. Which image depicts M82? (1) (d) Supernovae within the galaxy have produced bipolar outflow in this galaxy. What is the name of the most recent of these supernovae? (1) (e) Which image depicts this supernova event? (1) 6. Image 8 depicts the lenticular galaxy NGC 4993. (a) This galaxy was the site of what major development in the field of general relativity? (1) (b) This development was confirmed by matching it with the event seen in this image s upper-right inset. What type of event was this, and what was it caused by? (2) (c) What is the more common cause of such an event? (1) 7. SPT 0346-52 is a starburst galaxy about 12.7 billion ly from Earth. (a) What often-necessary component of a starburst galaxy is prominent in infrared images of SPT 0346-52? (1) (b) What type of star is most likely to form in such a galaxy? (1) (c) Is it common to find starburst galaxies at this distance? What does this suggest about starburst galaxies in the early universe? (2) 8. NGC 1128 is an irregular galaxy in the Abell 400 cluster. (a) What is the name of the radio source at the center of this galaxy? (1) (b) Which image depicts the structure of this radio source? (1) (c) What type of object is creating this source? (1) (d) What effect has the motion of this object through the dense cluster had on its radioactive structures? (1) 9. Sagittarius A* lies at the center of the Milky Way Galaxy. (a) Which image depicts the molecular cloud structure surrounding this object? (1) (b) Sagittarius A* is often referred to as a starved black hole. What does this mean in reference to this object s surrounding environment? (1) 10. Two images in this set depict Centaurus A. Identify these images, their respective wavelengths, and what key structure/feature is being highlighted in each. (3) 3
Section B: Each sub-question in this section is worth two points. The following questions 11-15 are worth one point for proper image identification and one for the correct multiple-choice answer. 11. Which image depicts the Antennae Galaxies? Given that the bright point sources seen are primarily compact, high-mass binary systems, this image was likely taken in: (a) Radio (b) Visible (c) X-Ray (d) Gamma Ray 12. Which image depicts the spiral galaxy M100 in infrared? The strongest regions of star formation in this image appear as: (a) Yellow (b) Blue (c) Green (d) White 13. Which image depicts the Chandra Deep Field South? From this image, it has been deduced that early black holes grew: (a) Via slow accumulation of matter (b) From seeds of over 10,000 solar masses (c) As isolated events distributed roughly evenly over time (d) Through a poorly-understood process known as x-ray stacking 14. Which image depicts the only known starburst galaxy in the Local Group? This galaxy s membership in this group was determined by: (a) Metallicity measurements of its constituent stars (b) Large-scale velocity measurements using Hubble s Law (c) The period-luminosity relationship for Cepheid variables (d) Magnitude measurements for use in the distance modulus 15. Which image depicts, in visible light, the site of one of the closest supernovae of its type detected in the last 50 years? Supernovae of this type have been used for all of the following purposes EXCEPT: (a) As secondary standard candles for extragalactic distances (b) For improved calibrations of the Hubble Constant (c) As approximate models for mass transfer in x-ray binaries (d) In proving the accelerated expansion of the universe 4
The sub-questions in the following questions 16-19 are worth two points each. 16. Star A is an RR Lyrae star in a globular cluster, which is observed to have an apparent magnitude of 20. (a) What is the distance to this globular cluster, in parsecs? (b) What is the parallax of Star A, in milli-arcseconds? (c) Star A has an effective temperature of 6,125 K. What is its radius, in Solar radii? 17. Star B and Star C orbit one another in a binary system with a separation of 50 AU. Assume that the two stars have circular orbits. Star B has a radius that is twice that of the Sun and an effective temperature of 3,500 K. (a) The period of Star B s orbit around their common barycenter is 112 years. What is the combined mass of Star B and Star C, in Solar Masses? (b) Star B lies 20 AU from the barycenter of the two orbits. What is the mass of Star B, in Solar masses? (c) What is the orbital velocity of Star B, in kilometers per second? (d) What is the orbital velocity of Star C, in kilometers per second? (e) The apparent magnitude of Star B is 5. How far away is this system, in parsecs? (f) What is the maximum apparent separation of Star B and Star C, in arcseconds? Is this separation visible to current telescopes (i.e., would this be a visual binary)? 18. Star D is a Cepheid variable star with a period of 15 days. For this problem, use the Cepheid period-luminosity relationship of M = [2.76 (log 10 P 1)] 4.16, where M is absolute magnitude and P is the period in days. (a) What is the absolute magnitude of Star D? (b) How many times more luminous is Star D than our Sun? (c) Star D is 100 parsecs away. What is its apparent magnitude? (d) What is the parallax of star D, in milli-arcseconds? (e) Star D has an effective temperature of 8,000 K. What is its radius, in Solar radii? (f) At what wavelength does the blackbody spectrum of Star D peak, in nanometers? 19. For the last question, let s have some fun! Estimate the following quantities to order of magnitude (that is, write 10 8 as 8 or 10 5 as 5, like in the event Fermi Questions ). (a) The mass of the Sun in Earth masses. (b) The mass of the Phoenix Cluster in units of the mass of the Milky Way Galaxy. (c) The mass of Sagitarrius A* in units of the mass of the Milky Way Galaxy. (d) The age of a weird Universe that has a Hubble constant of 10 8 km/s/mpc, in years. (e) The observable size of this weird universe with a Hubble constant of 10 8 km/s/mpc, in parsecs. 5
Image Sheet Image 1 Image 2 Image 3 Image 4 Image 5 Image 6 Image 7 Image 8 Image 9 Image 14 Image 10 Image 15 Image 11 Image 12 Image 16 Image 13 Image 17
Team name: KEY Team number: KEY 1. (a) Image 10 (b) Image 15 Answer Page: Section A (Max score: 40 points) (c) X-ray binary and millisecond pulsar (d) The neutron star of an x-ray binary is spun up by matter accreted from its companion 2. (a) M51 (b) Seyfert Galaxy, different from quasars in that the host galaxy is also detectable (c) Galactic merging 3. (a) Highest rate of star formation, most powerful x-ray producer (b) Central supermassive black hole (c) Quasar, evidenced by the optical and UV radiation in an accretion disc 4. (a) ESO 137-001 (b) The tail emanating from the galaxy to the bottom right corner (c) This tail is shutting down star formation within the galaxy by stripping it of cold gas, leading to star formation in the tail region 5. (a) Image 13 (b) There is a high concentration of dust in the galaxy s spiral arms (c) Image 1 (d) SN2014J (e) Image 16 6. (a) First confirmed measurement of gravitational waves (b) Gamma ray burst, caused by merging of two neutron stars (c) Produced in supernova event 7. (a) Large amounts of gas and dust (b) O or B type (c) Yes; this suggests that starburst galaxies were more common in the early universe as a result of frequent encounters 8. (a) 3C 75 (b) Image 11 (c) Double black hole binary (d) 9. (a) Image 7 It has swept them back to appear as curved jets of material (b) SgtA* exists in a gas-depleted environment, likely as a result of past explosive events 10. Image 3 depicts the object in radio, highlighting the intense regions of its radio jets. Image 6 depicts the object in color composite, showing x-ray jets and extreme star growth.
Team name: KEY Team number: KEY Answer Page: Section B (Max score: 50 points) 11. Image 2, C 12. Image 9, D 13. Image 17, B 14. Image 14, C 15. Image 16, C 16. (a) 70,795 parsecs (b) 0.014 milli-arcseconds (c) 5.35-6.55 Solar radii 17. (a) 8-12 Solar masses (b) 5-7 Solar masses (c) 4-7 kilometers per second (d) 7-10 kilometers per second (e) 6-10 parsecs (f) 6.28 arcseconds, yes 18. (a) -4 to -5 (b) 4000-8000 (c) 0.1-0.5 (d) 10 milli-arcseconds (e) 35-45 Solar radii (f) 300-400 nanometers 19. (a) 6 (5-7) (b) 3 (2-4) (c) -5 (-4 to -6) (d) 4 (3-5) (e) 3 (2-4) Use the bottom of the page as extra space to write answers: